1. Field of the Invention
The present invention relates to a stencil printing emulsion ink. More specifically, it relates to a stencil printing emulsion ink which has excellent drying properties and temperature suitability and has high ink concentrations in printed area and less bleeding and strike through thereof.
2. Description of the Prior Art
Stencil printing is carried out by platemaking using a stencil printing sheet and passing an ink through the perforated portions to print on a body to be printed such as paper and the like. This stencil printing has ease of preparation in the platemaking and, therefore, is used in board fields.
As for a stencil printing ink, a water-in-oil (W/O) type emulsion ink is generally used, and pigments and resin components are contained as a coloring agent in the oil phase component of the W/O type emulsion ink (Japanese Pat. Laid-Open Pub. Nos. 61-255967, 64-14284, 4-132777, 5-117565, etc.).
When a W/O type emulsion ink is used for printing on a substrate to be printed such as paper, generally the oil phase first permeates into the substrate to be printed as an outer phase of the emulsion, and then, a water phase as an inner phase thereof permeates and/or splashes the substrate. The oil phase contains the pigment components in such a W/O type emulsion ink, and it therefore takes a long time for the ink to dry. As a result, bleeding of the ink readily occurs. Also, the ink components permeate into the deep portion of the paper layer, and therefore, strike through of the ink readily occurs.
Furthermore, since the oil phase contains a resin component for improving the stable dispersion of the pigments and the fixation thereof onto the paper and this resin component undergoes a large viscosity change relative to temperature, there are disadvantages in that it is hard to ensure the viscosity stability of the ink and the permeation velocity of the ink into the paper is delayed due to the presence of the resin component.